1. Field of the Invention
This invention relates to digital array processors of the type having a plurality of identical interconnected cells which perform sequential transformation operations on data matrices under the control of a central processor and more particularly to unique forms of cell construction and interconnection between the processing cells.
2. Prior Art
U.S. Pat. No. 3,106,698 to Unger discloses a parallel digital processor consisting of a rectangular array of identical processing elements each having storage and logic processing capability. Each cell in the array is interconnected with its eight neighboring cells through multiplexers or link circuits. Data may be introduced directly to the accumulator of each cell from the equivalent cell of an input array. The data is simultaneously processed in each of the cells under control of a programmable master control that determines the elemental process step to be performed simultaneously by all of the cells and the transfer of information between cells through the multiplexer links. Data in the form of a rectangular array of data signals may be introduced directly to the processing cells and then a series of transformations are performed on the input data to arrive at an output matrix.
The transformations performed by the Unger system and subsequent systems of this type were based upon the status of the interconnected neighboring cells and are thus often termed "neighborhood processors". See for example the description of the systems constructed by the Image Processing Group at the University College of London, England, described in the Proceedings of the Third International Conference on Pattern Recognition, I.E.E.E., pages 728-735 and U.S. Pat. No. 3,979,728.
As a result of the large number of neighborhood cells that influence each transformation, the processor elements of these systems are necessarily relatively complex as are the multiplexers. As a result, economic restraints severely limit the practical size of the arrays that may be formed. Despite efforts to simplify cell structure the largest practical proposal that we are aware of involves 128.times.128 array described in Lai-WoFunc, A High Speed Image Processing Computer Proceedings 17th Annual Technical Symposium National Bureau of Standards, 1978. While these processors have utility for use on certain problems expressed as relatively small matrices involving substantial arithmetic computations they have not proved economical for a wide variety of large matrix problems such as high resolution image processing and wave equations.